Introduction: How Make an Oscillator (astable Multivibrator) and Pulse Width Regulator (monostable Multivibrator) With Logic Gates

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About: I use Instrustables to document my past projects and development of skills. I am an electrical engineering student from the University of Queensland.

This article provide the circuit diagram and a video demo of:

  1. astable multivibrator (Step 1 - 2)
  2. monostable multivibrator (Step 3 - 4)

Supplies

Information in the brackets indicate the exact supply that I used. You can use alternatives.

  1. 2X NOT gates (on 1X 74HCT04 IC chip)
  2. 1X OR gate (on 1X 74HCT32 IC chip)
  3. 1X capacitor (47 uF)
  4. 3X resistors (1MΩ, 710kΩ, 100kΩ)
  5. 1X LED
  6. Power supply for the logic gates (I just powered them from an I/O board)

Step 1: Circuit Diagram (astable Multivibrator)

The circuit diagram is the image above.

Step 2: Testing Astable Multivibrator

Above is the video demo

Step 3: Circuit Diagram (Monostable Multivibrator)

The circuit diagram is the image above.

Step 4: Testing Monostable Multivibrator

Above is the video demo

Step 5: Bistable Multivibrator

This article shows examples for monostable and astable multivibrator. This is a third type: Bistable, which is commonly referred to as a flipflop or SR latch (which is shown in the image above). There are plenty of information on flipflops on the web, so this article will not go into bistable multivibrators.


A type of bistable multivibrator is JK flipflops, on which I have an article about:

https://www.instructables.com/How-to-Build-a-Physical-JK-Flip-Flop-master-Slave-/